Horizontal bar chart with button scale transition

<!doctype html>
<html lang='en-GB'>
<head></head>
<style>
	p {
		font-family: sans-serif;
		font-size: 14px;
	}
	/*template styles*/
	.gia-chart-wrapper {
		max-width: 620px;
		margin: 0 auto;
	}
	/*chart styles*/
  	.x.axis line {
	    fill: none;
	    stroke: #dcdcdc;
	    stroke-dasharray: 1px 1px;
	    shape-rendering: crispEdges;
	    stroke-width: 1px;
	}
  	.y.axis line {
	    display: none;
	}
	.tick.g-baseline line {
	  	display: none;
	} 
	.x.axis text {
		font-family: sans-serif;
	    text-anchor: middle !important;
	    font-size: 12px;
		pointer-events: none;
		fill: #bdbdbd;
	}
	.y.axis text {
	  	display: none;
	}
	.g-axis-text {
	  	font-family: sans-serif;
	    text-anchor: start !important;
	    font-size:13px;
	    fill: #333333;
	    font-weight: 700;
	}
	.domain {
	    display: none;
	}
	.bar-positive {
	 	fill: #dcdcdc;
	}
	.bar-negative {
	  	fill: #d61d00;
	}
	.g-labels {
	  	font-family: sans-serif;
	  	font-size: 14px;
	  	fill: #767676;
	  	text-anchor: start !important;
	}
	button {
  		background-color: #ffffff;
		border: 1px solid #dcdcdc;
		border-radius: 15px;
		color: #333333;
		padding: 5px 8px;
		cursor: pointer;
		display: inline-block;
		margin-right: 10px;
		text-align: center;
		text-decoration: none;
		font-size: 12px;
		line-height: 20px;
		font-family: sans-serif;
	}
	button:focus {
	    outline: 0;
	}
    .active {
      	background-color: #333333;
     	color: #ffffff;
      	border: 1px solid #333333;
    }
    .gia-key {
    	margin-bottom: 15px;
    }
</style>

var widther = d3.select(".gia-chart").node().clientWidth;

var width = widther - margin.left - margin.right,
		    height = 500 - margin.top - margin.bottom;

//Appends the svg to the chart-container div
		var svg = d3.select(".gia-chart").append("svg")
			.attr("width", width + margin.left + margin.right)
		  	.attr("height", height + margin.top + margin.bottom)
		  	.append("g")
		  	.attr("transform", "translate(" + margin.left + "," + margin.top + ")");

//Format comma
		var format = d3.format("0,000")

//Creates the xScale 
		var xScale = d3.scale.linear()
		  	.range([0,width]);

//Creates the yScale
		var y0 = d3.scale.ordinal()
		  	.rangeRoundBands([height, 0], 0.1);

//Defines the y axis styles
		var yAxis = d3.svg.axis()
		  	.scale(y0)
		  	.tickSize(-width)
		  	.tickPadding(6)
		  	.ticks(4)
		  	.orient("left");

//Defines the y axis styles
		var xAxis = d3.svg.axis()
		  	.scale(xScale)
		  	.tickSize(-height)
		  	.tickPadding(6)
		  	.orient("bottom")
		  	.ticks(6);

//Loads the data
		d3.csv("budget.csv", ready);

function ready(err, data) {

if (err) throw "error loading data";

//FORMAT data
			data.forEach(function(d) {
				d.amount = +d.amount;
			    d.percentChange = +d.percentChange;
			    d.dollarChange = +d.dollarChange;
			});

//Sets the max for the xScale
		  	var maxX = d3.max(data, function(d) { return d.amount; });
		  	var minX = d3.min(data, function(d) { return d.amount; });

//Filters the data
		  	initialType = data.filter(function(d) { return d.type === "Billions of $";});

//Defines the domains
		  	xScale.domain(d3.extent(initialType, function(d) { return d.amount; })).nice();
		  	y0.domain(data.map(function(d) { return d.agency; }));

//Organizes buttons data
		  	var types = data.map(function(d) { return d.type;});
		  	var uniq = d3.set(types).values();

//Buttons
		  	var button = d3.select(".gia-key").selectAll("button")
			    .data(uniq)
			    .enter()  
			    .append("button")
			    .attr("class", function (d) {
			      	if ( d === "Billions of $" ) { return 'active'; }
			      	else { return 'not-active'; }
			    })
			    .text(function(d) {return d;})
			    .on("click", function(d) {
			        updateChartForType(d);
			        d3.select(".active").classed("active", false);
			        d3.select(this).classed("active", true);
			    });

var xAxisGroup = svg.append("g")
			    .attr("class", "x axis")
			    .attr("transform", "translate(0," + height + ")")
			    .call(xAxis);

xAxisGroup
		    	.selectAll("g")
		    	.classed("g-baseline", function(d) {return d == 0});

var yAxisGroup = svg.append("g")
		    	.attr("class", "y axis")
		    	.attr("transform", "translate(" + xScale(0) + ",0)")
		    	.call(yAxis);

//Append baseline 
		  	var baseline = svg.append("line")
			    .attr("y2", function(d) { return height; })
			    .attr("class", "added-baseline")
			    .attr("x1", xScale(0))
			    .attr("x2", xScale(0))
			    .attr("stroke-width", 1)
			    .attr("stroke", "#333333");

//Binds data to axis text  
		  	var axisLabelGroup = svg.selectAll("g-axis-text")
			    .data(initialType)
			    .enter()
			    .append("g")
			    .attr("class", "g-axis-text")
			    .attr("x", function(d) { return xScale(Math.min(0, d.amount)); })
			    .attr("y", function(d) { return y0(d.agency); })
			    .attr("width", function(d) { return Math.abs(xScale(d.amount) - xScale(0)); })
			    .attr("height", y0.rangeBand());

//Append axis labels
		  	var axisLabels = axisLabelGroup.append("text")
			    .text(function(d) { return d.agency; })
			    .attr("x", function(d) { return xScale(0); })
			    .attr("y", function(d) { return y0(d.agency) + 17; });

d3.selectAll(".g-axis-text")
		    	.attr("transform", "translate(-265,0)");

//Update chart on click
		  	function updateChartForType(typeId) {

//Filters to the new data
			    var typeData = data.filter(function(d) { return d.type === typeId;});

//Updates domains
			    xScale.domain(d3.extent(typeData, function(d) { return d.amount; })).nice();
			    y0.domain(data.map(function(d) { return d.agency; }));

bars
			    	.data(typeData)
			      	.transition().duration(1000)
			      	.attr("x", function(d) { return xScale(Math.min(0, d.amount)); })
			      	.attr("width", function(d) { return Math.abs(xScale(d.amount) - xScale(0)); });

xAxisGroup 
			      	.transition().duration(1000)
			      	.call(xAxis);

yAxisGroup 
			      	.transition().duration(1000)
			      	.call(yAxis);

baseline  
			      	.transition().duration(1000)
			      	.attr("x1", xScale(0))
			      	.attr("x2", xScale(0))     
		  	}

//RESPONSIVENESS
			d3.select(window).on("resize", resized);

function resized() {

//new margin
			    var newMargin = {top: 0, right: 6, bottom:30, left: 170};
				var newWidther = d3.select(".gia-chart").node().clientWidth;
			    var newWidth = newWidther - newMargin.left - newMargin.right;

//Change the width of the svg
			    d3.select("svg")
			    	.attr("width", newWidth + newMargin.left + newMargin.right);

//Change the xScale
			    xScale
			    	.range([0, newWidth]);

//Update the bars
			    bars
			    	.attr("width", function(d) { return Math.abs(xScale(d.amount) - xScale(0)); })
			    	.attr("x", function(d) { return xScale(Math.min(0, d.amount)); })

//Updates xAxis
			    d3.selectAll(".x.axis")
			      	.call(xAxis);

//Updates ticks
			    xAxis
			      	.scale(xScale);

//Updates yAxis
			    d3.selectAll(".y.axis")
			      	.attr("transform", "translate(" + xScale(0) + ",0)")
			      	.call(yAxis);

yAxis
			      	.tickSize(-newWidth);

baseline  
			      	.attr("x1", xScale(0))
			      	.attr("x2", xScale(0));
			};
		}
	</script>

</body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js